Shopkeepers display refrigerated or frozen products in temperature-controlled display cases, such as refrigerators with glass display doors or open-air, “coffin,” coolers. The refrigerators and freezers are referred to herein as “refrigerators.” Changes in temperature and humidity in the surrounding area cause condensation and frost to build up on the refrigerators. Condensation on doors obstructs visibility of the products, while condensation that builds on the outer surface of the refrigerator frame causes unsafe conditions when it falls and pools on the floor. It is therefore desirable to prevent the build-up of condensation and frost on refrigerators.
To combat condensation and frost, heaters are installed in refrigerator doors and frames, which raise the temperature of the door or frame sufficiently to eliminate condensation. Typically these heaters run constantly, but devices that control whether the heaters are on or off are known in the art. They are referred to generally as anti-sweat controllers. Anti-sweat controllers may use one or more condensation sensors attached to one or more doors or the frame, turning on the heaters when condensation is sensed. Traditionally, a single control box is used to control all the sensors of a given refrigerator. These devices fail, however, to prevent condensation because the heater is not activated until after condensation is sensed. It is known in the art to instead use a humidistat to sense humidity in the aisle and, when the humidity goes above a given level, the heater is turned on, often regardless of whether condensation is actually present. This increases energy consumption because the humidity in the aisle is not always indicative of the conditions on the door surface, so condensation may not be imminent. In this approach, the heaters are either constantly on or turned on unnecessarily. It would be desirable to prevent condensation with the minimum amount of heat, and consequent energy expenditure, necessary.
Anti-sweat controllers activate and deactivate door and frame heaters by supplying or denying an electrical current over a heater wire. In a refrigerator having a door heater and a frame heater, known anti-sweat controllers activate both heaters even if one heater is unneeded at that time. This design causes expenditure of up to twice as much energy as necessary, the most wasteful case being when the door and frame heaters are never needed simultaneously. It is desirable to better manage the power usage of the heaters to increase energy efficiency.
Refrigerators have fans to help regulate the interior temperature. Typically, a refrigerator has the same number of fans as it has doors, with fan motors connected to a common power supply. The fans are normally turned on at all times. Eventually, fan motors fail. The power usage of a failing fan motor may fluctuate for a period before its failure, and the power usage of all fan motors may spike after the failure. This may cause unnecessary temperature fluctuations that can lead to condensation, and also affects the refrigerator's energy efficiency. Additionally, fans are typically installed near the bottom of the refrigerator, where they are susceptible to water damage if the refrigerator floods during cleaning or a problem. It is desirable for an anti-sweat controller to monitor the fans and protect them from failure and overload.
Lighting a refrigerator also contributes heavily to the refrigerator's energy usage. In a commercial setting, periods may pass wherein no customers walk by the refrigerator, so illuminating the interior of the refrigerator is not needed. Known energy management techniques include placing a motion detector on the refrigerator or in the aisle and turning on the lights when motion is sensed. While this approach conserves some energy, it also shortens the life of refrigerator lights. It would be advantageous to control the lights in a way that does not shorten the life of the lamps, and further would be advantageous for the anti-sweat controller to control the lights in order to reduce the amount of required hardware for refrigerator energy management.
The anti-sweat controller may control a number of factors that must be set correctly to reduce energy consumption and eliminate condensation, including sensitivity of the sensors and duration of an “on” or “off” signal on a power circuit. To date, these factors have been measured and controlled by manually adjusting various currents and voltages on each control box with a multimeter. For a store with multiple refrigerators and multiple anti-sweat controllers, the multimeter must be plugged into each separate controller in order to adjust the entire system. Detecting the specific location of an electrical failure is frustrating and time consuming due to the need to test each separate device. Balancing the system becomes tedious. As a result, it is desirable to reprogram, monitor, and control an anti-sweat controller system without having to plug into each control box on each refrigerator and without having to make on-site visits to each store. Specifically, it would be desirable to provide a control box that could be programmed from a remote location using the Internet.
Known anti-sweat controllers connect the control box to the sensors with wires that transmit and receive data between the sensors and control box. Hardwiring the various sensors to the control box is problematic as it increases the time needed to install anti-sweat controllers. Additionally, the wires can be accidentally cut which results in a non-functioning anti-sweat controller which may require a qualified repairman to fix. It would be desirable to provide an anti-sweat controller that utilized wireless sensors to communicate with the control box to eliminate these communication wires.
Additionally, anti-sweat controllers are hardwired into the local power source, which results in difficult access for repair and replacement because the anti-sweat controllers must be unwired each time they are removed and rewired each time they are reinstalled. If the anti-sweat controller breaks, the fact that the system is integral with the local power source may cause the shopkeeper to be unable to set the system to keep the heaters on until a qualified repairman fixes the problem. Further, the dismantling and reconstruction cause safety issues while obstructing customer access to the refrigerators. It would be desirable to provide an anti-sweat controller that is connected to the power source with a quick-disconnect plug enabling it to be easier to install, repair and replace and that provides a means for the shopkeeper to mitigate problems if a controller fails.
Therefore, it is an object of this invention to provide an anti-sweat controller that operates a heater where condensation has not yet been detected but is anticipated. It is another object to increase energy efficiency by designing the anti-sweat controller to activate only the heaters that are needed at any time, and to manage the amperage of the heaters more efficiently. Another object is to monitor the power usage of refrigerator fans and generate an alert if fan power becomes erratic. A further object is to monitor the water level in the refrigerator to protect fans. It is another object to control the power usage of refrigerator lighting. It is another object of this invention to provide ease of programming, repair, and reinstallation by providing an anti-sweat controller with sensors and control boxes that communicate wirelessly. It is an additional object of the invention to provide remote monitoring and control of an anti-sweat controller over the internet.